Indoor Plumbing is Rare
In their attempt to keep their lives as simple as possible, some of the Amish don’t believe in having plumbing in their homes. Let us keep in mind there are around 40 subgroups of this religious group, and some subgroups are bound to be more extreme than others.
So it all comes down to what that particular group believes in. For instance, the Swartzentruber sect is extremely conservative and doesn’t believe in having running water in their taps or even flushing their toilets.